What is this program doing?

[gregorydouglas89]

What is this program doing?

  #include <iostream>
using namespace std;
int main()
{
cout<<"This program computes the average of ";
cout<<"a list of (nonnegative) exam scores."<<endl;
        double sum;
        int numberOfStudents;
        double next;
        char answer;
       
        do
        {
          
            cout<<"Enter all the scores to be averaged."<<endl;
            cout<<"Enter a negative number after ";
            cout<<"you have entered all the scores."<<endl;
            sum = 0;
            numberOfStudents = 0;
            cin>>next;
            while (next >= 0)
            {
                sum = sum + next;
                numberOfStudents++;
                cin>>next;
            }
            if (numberOfStudents > 0)
               cout<<"The average is "<<(sum / numberOfStudents)<<endl;
            else
               cout<<"No scores to average."<<endl;
            cout<<"Want to average another exam?"<<endl;
            cout<<"Enter y for Yes or n for no."<<endl;
            cin>>answer;
        }
        while (answer=='y'|| answer=='Y');
    
   
    system ("pause");
    return 0;
}

[keskiverto]

Do you regognize any of the control structures?
What does the program tell to the user?

[gregorydouglas89]

if i enter a negative number it averages out only the non negative numbers.

if i enter any character other than a number the program goes into a infinite loop